Gearless traction elevators driven by electric motors are known in the art. Such elevators are powered by lower speed electric motors, compared to geared traction elevators. In a gearless traction elevator, a traction sheave is directly coupled with a shaft which is rotated by the electric motor. The traction sheave drives one or more cables or ropes which are connected on one end to the elevator and on the other end to a counterweight.
In one known method of coupling a traction sheave to a motor shaft, the traction sheave is rigidly fitted and aligned on the motor shaft via a key on the rotating shaft. The traction sheave may rattle about the motor shaft and result in noisy operation. The motor shaft may also be prematurely damaged because of an improper fit between the traction sheave and the motor shaft and may result in hardening of the exterior of the shaft, thereby making it brittle.
In view of the above, it is desirable to obtain a coupling arrangement for mounting such a traction sheave directly onto a shaft of an electric motor which enables a proper fit between the sheave and the motor shaft, reduces the possibility of damage to the motor shaft, and is less cumbersome.